Well, if it was only the PCB layout, I'd probably have done it myself long ago. But there are a few issues with the prototype design that I wanted to solve before creating the production PCB:

The prototype connects NES signals CPU R/W, PRG /CE, PPU /R and CPU M2 (cartridge) to MD signals VA20 .. VA17 (Retrode). The Retrode can change all of those signals at once. IIRC, connecting M2 to VA17 also had the reason to minimize the total wire length of the M2 connection in the prototype.

The problem here is that CPU M2 is high active. The current initial state of the Retrode has VA20 .. VA17 all high, which could cause a NES cartridge to enable outputs of an SRAM chip, if present (connected to the lower data byte MD pins). Initializing VA17 to low might not be ideal either, because that would enable something on SMS cartridges (/MC-F). So, VA17 wasn't the best choice for M2.

The Retrode 1 has gamepad signals on VA20 .. VA17. They are also connected on the N64 plug-in.

In the prototype, NES signal PPU /W is pulled high, not connected to any MD signal. But there's a game which uses CHR RAM for savegames, and PPU /W would be required for writing to that CHR RAM. So I wanted to add a connection for PPU /W. It might also be useful for detecting whether a game has CHR ROM or CHR RAM.

I considered connecting the NES signal CIRAM A10 to the GND pin A32 of the MD connector, which the Retrode uses for cartridge detection. This might allow the Retrode to quickly and easily detect that the connected cartridge is a NES game, and which mode of "nametable mirroring/arrangement" it uses (an information for the .nes file header). But I can't say for sure that it would work with all NES games. E. g., some mapper might block the signal until initialized.

I considered reordering some of the address and data lines to make routing easier (more parallel, less crossing wires). The firmware would have to reorder the address and data bits accordingly.

I never measured the power consumption of the Retrode with a NES cartridge inserted.

Nevertheless, having a professional designer create the new PCB layout seems like the only realistic way to get it done soon. So, go ahead. Maybe the designer can prepare the PCB for later modding with respect to the above mentioned issues. Or maybe someone else with good knowledge of the NES and Retrode has suggestions how to address those issues.

I'll try and help as much as I can. I'll send you a PM with additional information.

See the files attached to my original post about the prototype. The relevant schematic is "retrode-sega-to-nes-without-ics-v2a.sch". The "... pin assignments.txt" file contains roughly the same information. The lbr files will be required for making the PCB (brd file), too.The files "nes-and-sega-to-pads-v3a.*" describe the prototype PCB and are quite useless for the new design.